<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    /* div,p,h1{color:red;} */
    /* 选择body>h1之后的直接子元素 */
    /* 选择body h1选中body之后的所有子元素h1 */
    body h1{color:blue;}
    </style>
</head>
<body>
    <div>div</div>
    <div>
        <h1>h1</h1>
    </div>
    <p>p</p>
    <h1>h1</h1>

</body>
</html>